Abstract: Silage maize (Zea mays L.) has become a crucial grain-forage dual-purpose crop in Chinese agriculture. As one of the most widely used forage crops, its cultivation potential is significantly affected by the effective accumulated temperature. Although a large number of research works have been carried out to improve the yield and nutritional quality of silage maize, the research on the planting system of double-crop silage maize in different regions is relatively limited. In order to rationally plan the planting climate regions of double-crop silage maize in Hebei Province, this study conducted a field experiment in 2024 at the Nanpi Ecological Agriculture Experimental Station (38.04°N, 116.40°E) in Cangzhou City, Hebei Province. This area is a typical semi-arid agricultural ecosystem in the North China Plain. The experimental materials included ten maize varieties suitable for both grain and forage use with growth periods that could meet the requirement of two crops a year: ‘Jinling 327’ ‘Jiyuan 888’ ‘Ganyu 331’ ‘Huayu 698’ ‘Liangyu 99’ ‘Weike 966’ ‘Boke 1066’ ‘Dongdan 1775’ ‘Zhengdan 958’ and ‘Beinong 368’. During the whole growing season, the phenological periods of each variety were recorded, including the emergence stage, jointing stage, silking stage, blister stage, milk stage, and early dough stage, and the effective accumulated temperature (the sum of the daily average temperatures above 10 ℃ during the growth period) of each variety in each growing season was calculated. According to the average effective accumulated temperature (Ai) of the two seasons, the tested varieties were divided into three different maturity groups: early-maturing (Ai<1 200 ℃∙d), medium-maturing (1 200≤Ai<1 250 ℃∙d), and late-maturing (Ai≥1 250 ℃∙d), thus obtaining six possible double-crop combinations: early-maturing-early-maturing, early-maturing - medium-maturing, early-maturing - late-maturing, medium-maturing - medium-maturing, medium-maturing - late-maturing, and late-maturing - late-maturing. In order to infer these experimental results at the spatio-temporal scale, this study integrated the extensive meteorological data sets of 123 county-level meteorological stations in Hebei Province over 45 years (1976−2020), implemented a strict data quality control protocol, and used the Inverse Distance Weighting (IDW) interpolation method to estimate the missing observations. This method ensured the complete spatial coverage while maintaining the integrity of the thermal regime analysis. The results showed that the overall interannual variation rate of the effective accumulated temperature ≥0 ℃ in Hebei Province was 7.37 ℃∙d∙a⁻¹, showing a gradually increasing trend; the areas with relatively small effective accumulated temperature (≤1 100 ℃∙d) were all located in Zhangjiakou City and Chengde City from 1976 to 2020, and the range gradually decreased but the trend was not obvious; the range of larger values (≥2 200 ℃∙d) gradually expanded and the trend was relatively obvious. By 2020, the trend of climate warming had caused the area where double-crop silage maize could be planted to expand northward, and all six combinations had areas where they could be planted in Hebei Province. This study shows that climate warming has greatly changed the planting potential of double-crop silage maize in Hebei Province. In conclusion, with the continuous global climate warming, the increase in the effective accumulated temperature in the future may further increase the heat resources for double-crop silage maize and may expand the feasible planting area of different maturity combinations. The methodological framework developed here, combining precise field experiments with powerful climate analysis, provides a model for evaluating the adaptation of planting systems facing similar climate-driven transitions in other temperate regions. Future research should incorporate more environmental variables and economic factors to develop comprehensive decision support tools for farmers and policymakers to address the challenges and opportunities of climate change.s